THE INFLUENCE OF MHD TURBULENCE ON THE STABILITY OF A TANGENTIAL DISCONTINUITY

The stability conditions for a tangential discontinuity in a turbulent medium are obtained on the basis of ideal magnetohydrodynamic equatio ns. The turbulence is represented as a high-frequency, short-wavelengt h background with respect to the mean parameter values and coherent pe rturbations. The two cases of weakly and strongly compressible plasma are analyzed in detail. In the former case, anisotropic turbulence can result in the stabilization of a tangential discontinuity. The analog y of this limiting case with the firehose instability in an anisotropi c plasma is noted. In a strongly compressible (clumpy) medium, the tur bulence is a destabilizing factor, though new stable directions in the propagation of the perturbation appear (in comparison with the lamina r case). Instability increments for discontinuities in the interplanet ary medium are estimated.